The present invention relates to an electrically controlled braking system for a vehicle.
Electrically controlled braking systems are known in varied form. For example, German Published Patent Application No. 196 34 567 describes an electrically controlled braking system with a decentralized structure, in which a first control module for forming reference variables dependent on the driver""s input, and second control modules for controlling or regulating the actuators of the wheel brakes are interconnected via at least one communication system. The braking system described is intended to fulfill both a service-brake function and a parking-brake function. Measures with respect to this requirement cannot be gathered from the known related art.
An object of the present invention is to specify an electrical braking system in which, in addition to a service-brake function, a parking-brake function is implemented as well.
For example, the German Published Patent Application No. 197 52 543 describes a brake-adjusting device which is actuated for applying braking force to the wheel brake. In addition to this adjusting device, a preferably bistable electromagnetic brake is provided for fixing this control element in its respective brakes-applied mode. By driving this locking device, the application force applied by the final brake control element is maintained, even without driving the final brake control element. A parking-brake function can be implemented by this locking or arresting mechanism. No instructions are given for integrating such a control element into a decentralized control structure.
Furthermore, parking brakes are also known in conjunction with hydraulically and/or pneumatically operated disc brakes or drum brakes, in which the parking-brake action is provided by driving an electrically operable actuator (e.g., German Published Patent Application No. 196 48 581).
The separate transmission of service-brake control signals and parking-brake control signals, which are generated in one central control module on the basis of the corresponding actuating signals, via the communication system to the control modules actuating the wheel brakes provides a simple, well-managed, trouble-insusceptible integration of the service-brake function and the parking-brake function into one decentrally controlled electrical braking system.
It is particularly advantageous that no additional cabling expenditure is necessary even for actuating a final wheel-brake control element together with an arresting or locking device, since the control signals for both final control elements are supplied via the communication system which is present in any case. In contrast to single lines, the use of the communication system permits a fail-safe transmission for the parking-brake control signal.
It is also advantageous that the function of driving the parking-brake, arresting or locking device can be monitored by monitoring measures - known for themselves - of the electrical transmission line, from the adjusting-device control module controlling the respective wheel brake, and can be integrated into the control module.